Vehicle vision system utilizing multiple cameras and ethernet links

ABSTRACT

A vehicular vision system includes a plurality of cameras disposed at the vehicle and having respective fields of view exterior of the vehicle and being operable to capture frames of image data. Image data captured by each of the cameras is provided to an ECU via an ETHERNET link from the respective camera to the ECU. At least one control signal for controlling operation of each camera is provided from the ECU to the respective camera via the respective ETHERNET link. Image data captured by at least one of the cameras is processed at the ECU to detect an object present exterior of the equipped vehicle, wherein the object is a vehicle that is approaching the equipped vehicle and that is traveling in a traffic lane adjacent to a traffic lane in which the equipped vehicle is traveling.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/338,781, filed Oct. 31, 2016, now U.S. Pat. No. 9,912,841,which is a continuation of U.S. patent application Ser. No. 14/097,581,filed Dec. 5, 2013, now U.S. Pat. No. 9,481,301, which claims the filingbenefits of U.S. provisional application Ser. No. 61/733,598, filed Dec.5, 2012, which is hereby incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates to vehicles with cameras mounted thereonand in particular to vehicles with one or more exterior-facing cameras,such as forward facing cameras and/or sideward facing cameras and/orrearward facing cameras.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties.

SUMMARY OF THE INVENTION

The present invention provides a camera for a vision system thatutilizes one or more cameras or image sensors to capture image data of ascene exterior (such as forwardly) of a vehicle and provides a displayof images indicative of or representative of the captured image data.The vehicle vision system automatically synchronizes a number of camerasof the vision system without changing the system architecture. Thevehicle vision system powers on or initializes a camera, and starts thecamera synchronous to an ECU reference timing, and then regulates thecamera timing synchronous to the ECU reference timing. The system mayadjust or regulate the camera or sensor between a fast mode and a slowmode depending on whether a maximum buffer level achieved duringprocessing exceeds a selected maximum buffer threshold and whether aminimum buffer level achieved during processing is below a selectedminimum buffer threshold. By adjusting the mode of the camera or sensor,the system can regulate the camera and synchronize the camera to the ECUtiming.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system thatincorporates cameras in accordance with the present invention;

FIG. 2A is a schematic of a multi-camera system in accordance with thepresent invention;

FIG. 2B is a schematic of a multi-camera system with a hub in the pathof video data transmission in accordance with the present invention,with some cameras (Cam1 and Cam2) running over the hub and some cameras(CamN) connected to the ECU directly;

FIG. 3A is a schematic of an ECU structure of the vision system of thepresent invention, showing on-the-fly image processing without an imagebuffer, and behind the buffers the image pixels of all of the camerasare clock aligned;

FIG. 3B is another schematic of an ECU structure of the vision system ofthe present invention, showing image processing with an image bufferwithin the pipeline;

FIG. 4 is a flow chart showing the synchronization main states of thepresent invention;

FIG. 5A is a flow chart of a smart camera operation in accordance withthe present invention, showing a sequence when starting from reset;

FIG. 5B is a flow chart of a smart camera operation in accordance withthe present invention, showing a sequence when starting from standby;and

FIG. 6 is a flow chart of a regulation of the smart camera of the visionsystem of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 includes an imaging system or vision system 12that includes one or more imaging sensors or cameras (such as a rearwardfacing imaging sensor or camera 14 a and/or a forwardly facing camera 14b at the front (or at the windshield) of the vehicle, and/or asidewardly/rearwardly facing camera 14 c, 14 b at the sides of thevehicle), which capture images exterior of the vehicle, with the camerashaving a lens for focusing images at or onto an imaging array or imagingplane of the camera (FIG. 1). The vision system 12 is operable toprocess image data captured by the cameras and may provide displayedimages at a display device 16 for viewing by the driver of the vehicle.Optionally, the vision system may process image data to detect objects,such as objects to the rear of the subject or equipped vehicle during areversing maneuver, or such as approaching or following vehicles orvehicles at a side lane adjacent to the subject or equipped vehicle orthe like.

General Description:

A typical multi-camera video system as shown in FIG. 2A comprisesseveral (2 to N) satellite cameras, an electronic control unit (ECU) anda display. Typically, the satellite cameras (such as exterior facingcameras such as cameras 14 a, 14 b, 14 c, 14 d of FIG. 1) are connectedvia a common video interface (such as NTSC (National Television SystemCommittee) or PAL (Phase Alternating Line) or CameraLink or LVDS or thelike) and an additional control channel (CAN, LIN, UART) to the ECU.Ethernet and LVDS (Low Voltage Differential Signaling) may combine thevideo and the control channel over one interface. All of the mentionedinterfaces are not able to distribute a common clock, generated insidethe ECU, to the cameras. Therefore, all of the cameras and the ECU havetheir own clock sources or timing, although they normally have the sametypical clock frequencies.

In such a system, it is often desired or required that the image signalprocessing uses images that are sensed at the same time to combine themwithout artifacts to the display output (particularly for generating asurround view display image based on image data captured from multipleexterior viewing cameras of the vehicle). Therefore, the sensors have torun synchronized all the time. This means their frame rates have to besubstantially or exactly the same and the sensor readout has to besubstantially or nearly at the same video line at a time. They thustypically run synchronously.

The present invention provides a method that allows the system tosynchronize any number of cameras without changing the systemarchitecture. Although only one camera is discussed in the descriptionbelow, the description applies to all of the cameras of a multi-cameravision system because every camera of a plurality of cameras of thevehicle may be synchronized to an ECU reference timing individually.

When running the video data over common high performance busses (such asFlexray or the like), there may be hubs instead of an ECU that thecameras are interfacing with and synchronized to. For example, see FIG.2B, which shows a system that has some cameras (Cam1 and Cam2) connectedto and interfacing with a hub (with another camera or other cameras(CamN) connected to and interfacing with the ECU directly. Although onlythe interfacing to an ECU is discussed in the description below, thepresent invention and description below applies to both a hub and an ECUas reference timing providing node to the camera or cameras.

ECU Entities for Synchronization:

The components for realizing the synchronization tasks in the ECU areshown in FIG. 3A. The camera video data Cam_Video is coming in to or isreceived by the Video Line Buffer via the Video Interface controlled bythe transfer clock Cam_CLK. The side signals Cam_HS and Cam_VS aresignaling the line period with blanking (horizontal timing) and frameperiod with blanking (vertical timing). Data is only written to theVideo Line Buffer when Cam_HS and Cam_VS both do not signal a blankphase. The Video Line Buffer is organized in a FIFO (first in first out)manner, containing only the pixel data of about 1 to 2 lines or more.This depends of the clock tolerances and how fine the sensor timing canbe adjusted.

The Reference Timing Generator produces the internal pixel referenceclock Ref_CLK and timing signals Ref_HS and Ref_VS, which nearly havethe same timing properties as the camera signals. If the referencetiming signals indicate valid data, the Video Line Buffer is read.Finally, Cam_CLK, Cam_Video, Cam_HS and Cam_VS are replaced by Ref_CLK,Sync_Video, Ref_HS and Ref_VS. This at first has the effect that thecamera data path is clock-synchronized to the ECU reference timing.

Then the Camera Sync Control instance has to control and ensure that thelines and frames are synchronized. This is achieved by taking care thatprimarily the camera is started at a well-defined time or timing point,so that the start of the first frame is written to the Video Line Bufferwhen the reading also starts. Secondly, the camera timing has to beprogrammed in a manner so that it is definitely a bit faster than thereference timing. This will lead to an increasing Buffer_level of theVideo Line Buffer during the frame processing. After some frames, theBuffer_level arrives at a certain upper level threshold c_th_upper,where the camera sensor has to be adjusted to a timing, which is a bitslower than the reference timing. After this, the Buffer_level willdecrease frame by frame. When the value arrives at a certain lower levelthreshold c_th_lower, the sensor has to be re-adjusted to the fastertiming and so on. The threshold values c_th_upper and c_th_lower areconstants, which have to be well determined or calculated to avoid abuffer overflow or underflow at all conditions.

Ref_VS is required to find the right start point for the camera inCamera Sync Control. A physical Power Switch on the ECU to control thecamera power is not required but may be an optional element of thesystem. The method or system of the present invention also works ifcamera power is switched somewhere else, such as, for example, by thevehicle ignition or a system activation switch.

Synchronization for Image Pipeline with Image Buffer:

In the case where an image buffer is available in the image pipeline,the FIFO or buffer has to equalize only the drifts between the sensorclock and the reference clock during one line. Behind the FIFO, theimage alignment still has a drift of about 1-2 lines. This will besolved at the image buffer during the vertical blank period. The mainbenefit of this solution is the much smaller FIFO. Optionally, thesolution with the larger line buffer FIFO (FIG. 3A) may also be used insystems with an image buffer in the pipeline.

The input structure for an ECU with an image buffer in the imagepipeline is shown in FIG. 3B. In this case, the Cam_HS and Cam_VSsignals are just sampled to the reference clock Ref_CLK and delayed bysome clock period or time period. The delay has to be realized in amanner that the active periods of the lines are conserved. During theblank phases, the FIFO is always empty. When a line starts, it iswritten from the camera side. Optionally, and desirably, when it isfilled about half way, the reading also starts. The difference to thesolution in FIG. 3A is that Sync_HS and Sync_VS in the system of FIG. 3Bare still dependent from the sensor timing and therefore exist inparallel for each camera like Sync_Video. The Camera Sync Control is thesame in both systems. Instead of the buffer level, there is calculated(in the system of FIG. 3B) the distance in clock cycles between thestart of frame (SOF) of the Reference Timing at Ref_VS and the SOF ofthe sensor timing at Sync_VS. This is the task of the Calc_Distanceblock.

Camera Sync Control—Main Tasks:

To achieve a multi-camera system running synchronously in accordancewith the present invention, two tasks are performed:

-   -   1) Start the camera synchronous to the ECU reference timing; and    -   2) Hold (regulate) the camera timing synchronous to the ECU        timing.        FIG. 4 shows the main tasks in a state-machine depending of the        camera power (POWER_on).        Start Camera from Reset Task:

A flowchart of the start camera task is shown in FIG. 5A. After startingor powering-on a camera, the link from ECU to camera is initialized,regardless of which interface technology is used. After the link isinitialized, a communication to the camera sensor and optional partssuch as, for example, an EEPROM or the like, is established.

The EEPROM may contain production and calibration data, which is oftennamed intrinsic data. This camera intrinsic data should be read next,because later-on it may be more time consuming or complicated.

If the startup time of the sensor is varying from part to part, it maybe helpful to measure individual behavior and adjust the start pointindividually. A good period to measure is reset to the start of frame(SOF) or reset to the end of frame (EOF). If this is likely constant,the measurement step with its reset before can be left-out.

At the end, the sensor has to be reconfigured for application specificneeds. The startup time from the sensor, in that case, is different fromthe startup time with default values after the reset. However, thedifference of these two times will be constant for all parts. Withknowledge of that time difference or delta time and under considerationof known or selected tolerances, the starting point related to the ECUreference Ref_VS can be calculated, so that the sensor will start itsfirst frame slightly before the ECU wants to read it from the FIFO. Thestart point is then awaited after the triggering edge of Ref_VS.

The startup of the sensor is initiated with a reset. This can be doneeither via hardware (HW), such as by pin toggling or the like, or viasoftware (SW), such as by sending a command or the like. Then theapplication specific configurations are sent to the sensor, where at itsend the sensor has the correct frame timing. At the end of this task,the sensor's start of its first frame will be synchronous with orsynchronized to the ECU reference timing and first read.

Start Camera from Standby Task:

A flowchart of the start camera task is shown in FIG. 5B. After startingor powering-on a camera, the link from ECU to camera is initialized,regardless of which interface technology is used. After that, acommunication to the camera sensor and optional parts, such as, forexample, an EEPROM or the like, is established.

The EEPROM may contain production and calibration data, which is oftennamed intrinsic data. This data should be read next, because later-on itmay be more time consuming or complicated to accomplish.

Optionally, the sensor may be configured with application specificsettings or application specific settings may be loaded into the sensor.

After that, the sensor has to be put into the standby mode where theapplication specific settings may not be lost. The sensor start timingfrom standby to run mode may then be measured. If the startup time ofthe sensor is varying from part to part, it may be helpful to measureindividual behavior and adjust the start point individually. A goodperiod to measure is run to start of frame (SOF) or run to end of frame(EOF). If this is likely constant, the measurement step can be left-out.

Then the calculation of the starting point takes place which is relatedto the ECU reference Ref_VS, so that at the end the sensor will startthis first frame slightly before the ECU wants to read it from the FIFO.

The start point is then awaited relating to the triggering edge ofRef_VS and the startup of the sensor is initiated by setting the sensorinto run mode. At the end of this task, the sensor's start of firstframe will be synchronous to the ECU reference timing and first read.

Regulation Task:

A flowchart of the regulation task is shown in FIG. 6. Buffer_Level fromFIG. 3A and Distance from FIG. 3B have the same meaning for theRegulation Task. The regulation task is a repeating process startedonce. As described before, the sensor is normally operating a bit fasterthan the ECU reference timing. This is the fast mode.

While the end of frame (EOF) is awaited, that system saves the maximumoccurred Buffer_Level in fast mode to max_buffer_level. After the end offrame (EOF), the max_buffer_level is compared to the c_th_upperthreshold. If the max buffer level is not greater than the c_th_upperthreshold, then the buffer takes no risk to overflow in the next frameand the sensor can continue in fast mode.

Otherwise, if the max buffer level is greater than the c_th_upperthreshold, the sensor timing is switched to the slow mode. This is doneduring the vertical blanking period before the start of frame (SOF).

While the end of frame is awaited, the system saves the minimum occurredBuffer_Level in the slow mode to min_buffer_level. After EOF, themin_buffer_level is compared to the c_th_lower threshold. If the minimumbuffer level is not smaller than the c_th_lower threshold, then thebuffer takes no risk to underflow in the next frame and the sensor cancontinue in slow mode. Otherwise, if the minimum buffer level is smallerthan the threshold, the sensor timing is switched to the fast mode. Thisis done during the vertical blanking period before SOF. The regulationtask then restarts again.

Optionally, the regulation task may also operate well if themin_buffer_level is not calculated and checked. In such an application,the fast mode follows one frame period of slow mode automatically. Thisdepends on the adjustment granularity of the sensor and the systemdesign.

Switching Sensor Timing:

In principle, there are two possibilities to slow down the sensortiming. A first option is to add an additional blank line. This enlargesthe frame period by one line period. However, if the sensor has arolling shutter, this method won't work, because it may conflict withthe exposure control.

A second and preferred option is to add blank pixels to the lines. Inthis case the frame period enlarges by the number of lines multipliedwith the added pixels per row. In this case, the exposure control isalso influenced, but in a much smoother way, which cannot be recognizedby the viewer viewing displayed images captured by the imager anddisplayed on a display.

Therefore, the present invention provides a system that automaticallysynchronizes a number of cameras of a vehicle vision system withoutchanging the system architecture. The system of the present inventionpowers on or initializes a camera, and starts the camera synchronous toan ECU reference timing, and then regulates the camera timingsynchronous to the ECU reference timing. The system may adjust orregulate the camera or sensor between a fast mode and a slow modedepending on whether a maximum buffer level achieved during processingexceeds a selected maximum buffer threshold and whether a minimum bufferlevel achieved during processing is below a selected minimum bufferthreshold. By adjusting the mode of the camera or sensor, the system canregulate the camera and synchronize the camera to the ECU timing.

The vehicle may include any type of sensor or sensors, such as imagingsensors or radar sensors or lidar sensors or ladar sensors or ultrasonicsensors or the like. The imaging sensor or camera may capture image datafor image processing and may comprise any suitable camera or sensingdevice, such as, for example, an array of a plurality of photosensorelements arranged in at least 640 columns and 480 rows (preferably amegapixel imaging array or the like), with a respective lens focusingimages onto respective portions of the array. The photosensor array maycomprise a plurality of photosensor elements arranged in a photosensorarray having rows and columns. The logic and control circuit of theimaging sensor may function in any known manner, and the imageprocessing and algorithmic processing may comprise any suitable meansfor processing the images and/or image data.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 7,005,974;5,760,962; 5,877,897; 5,796,094; 5,949,331; 6,222,447; 6,302,545;6,396,397; 6,498,620; 6,523,964; 6,611,202; 6,201,642; 6,690,268;6,717,610; 6,757,109; 6,802,617; 6,806,452; 6,822,563; 6,891,563;6,946,978; 7,859,565; 5,550,677; 5,670,935; 6,636,258; 7,145,519;7,161,616; 7,230,640; 7,248,283; 7,295,229; 7,301,466; 7,592,928;7,881,496; 7,720,580; 7,038,577; 6,882,287; 5,929,786 and/or 5,786,772,and/or International Publication Nos. WO 2011/028686; WO 2010/099416; WO2012/061567; WO 2012/068331; WO 2012/075250; WO 2012/103193; WO2012/0116043; WO 2012/0145313; WO 2012/0145501; WO 2012/145818; WO2012/145822; WO 2012/158167; WO 2012/075250; WO 2012/103193; WO2012/0116043; WO 2012/0145501; WO 2012/0145343; WO 2012/154919; WO2013/019707; WO 2013/016409; WO 2012/145822; WO 2013/067083; WO2013/070539; WO 2013/043661; WO 2013/048994; WO 2013/063014, WO2013/081984; WO 2013/081985; WO 2013/074604; WO 2013/086249; WO2013/103548; WO 2013/109869; WO 2013/123161; WO 2013/126715; WO2013/043661 and/or WO 2013/158592 and/or U.S. patent application Ser.No. 14/082,573, filed Nov. 18, 2013 and published May 22, 2014 as U.S.Publication No. US-2014-0139676; Ser. No. 14/082,574, filed Nov. 18,2013 and published May 22, 2014 as U.S. Publication No. US-2014-0138140;Ser. No. 14/082,575, filed Nov. 18, 2013 and published Jun. 5, 2014 asU.S. Publication No. US-2014-0156157; Ser. No. 14/082,577, filed Nov.18, 2013, now U.S. Pat. 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No.61/837,955, filed Jun. 21, 2013; Ser. No. 61/836,900, filed Jun. 19,2013; Ser. No. 61/836,380, filed Jun. 18, 2013; Ser. No. 61/834,129,filed Jun. 12, 2013; Ser. No. 61/833,080, filed Jun. 10, 2013; Ser. No.61/830,375, filed Jun. 3, 2013; Ser. No. 61/830,377, filed Jun. 3, 2013;Ser. No. 61/825,752, filed May 21, 2013; Ser. No. 61/825,753, filed May21, 2013; Ser. No. 61/823,648, filed May 15, 2013; Ser. No. 61/823,644,filed May 15, 2013; Ser. No. 61/821,922, filed May 10, 2013; Ser. No.61/819,835, filed May 6, 2013; Ser. No. 61/819,033, filed May 3, 2013;Ser. No. 61/816,956, filed Apr. 29, 2013; Ser. No. 61/815,044, filedApr. 23, 2013; Ser. No. 61/814,533, filed Apr. 22, 2013; Ser. No.61/813,361, filed Apr. 18, 2013; Ser. No. 61/810,407, filed Apr. 10,2013; Ser. No. 61/808,930, filed Apr. 5, 2013; Ser. No. 61/807,050,filed Apr. 1, 2013; Ser. No. 61/806,674, filed Mar. 29, 2013; Ser. No.61/793,592, filed Mar. 15, 2013; Ser. No. 61/772,015, filed Mar. 4,2013; Ser. No. 61/772,014, filed Mar. 4, 2013; Ser. No. 61/770,051,filed Feb. 27, 2013; Ser. No. 61/770,048, filed Feb. 27, 2013; Ser. No.61/766,883, filed Feb. 20, 2013; Ser. No. 61/760,366, filed Feb. 4,2013; Ser. No. 61/760,364, filed Feb. 4, 2013; Ser. No. 61/756,832,filed Jan. 25, 2013; Ser. No. 61/754,804, filed Jan. 21, 2013; Ser. No.61/736,104, filed Dec. 12, 2012; Ser. No. 61/736,103, filed Dec. 12,2012; Ser. No. 61/734,457, filed Dec. 7, 2012, and/or Ser. No.61/733,093, filed Dec. 4, 2012, which are all hereby incorporated hereinby reference in their entireties. The system may communicate with othercommunication systems via any suitable means, such as by utilizingaspects of the systems described in International Publication Nos.WO/2010/144900; WO 2013/043661 and/or WO 2013/081985, and/or U.S. patentapplication Ser. No. 13/202,005, filed Aug. 17, 2011, now U.S. Pat. No.9,126,525, which are hereby incorporated herein by reference in theirentireties.

The imaging device and control and image processor and any associatedillumination source, if applicable, may comprise any suitablecomponents, and may utilize aspects of the cameras and vision systemsdescribed in U.S. Pat. Nos. 5,550,677; 5,877,897; 6,498,620; 5,670,935;5,796,094; 6,396,397; 6,806,452; 6,690,268; 7,005,974; 7,123,168;7,004,606; 6,946,978; 7,038,577; 6,353,392; 6,320,176; 6,313,454 and6,824,281, and/or International Publication No. WO 2010/099416,published Sep. 2, 2010, and/or PCT Application No. PCT/US10/47256, filedAug. 31, 2010 and published Mar. 10, 2011 as International PublicationNo. WO 2011/028686, and/or U.S. patent application Ser. No. 12/508,840,filed Jul. 24, 2009, and published Jan. 28, 2010 as U.S. Pat.Publication No. US 2010-0020170, and/or PCT Application No.PCT/US2012/048110, filed Jul. 25, 2012 and published Jan. 31, 2013 asInternational Publication No. WO 2013/016409, and/or U.S. patentapplication Ser. No. 13/534,657, filed Jun. 27, 2012 and published Jan.3, 2013 as U.S. Publication No. US-2013-0002873, which are all herebyincorporated herein by reference in their entireties. The camera orcameras may comprise any suitable cameras or imaging sensors or cameramodules, and may utilize aspects of the cameras or sensors described inU.S. patent application Ser. No. 12/091,359, filed Apr. 24, 2008 andpublished Oct. 1, 2009 as U.S. Publication No. US-2009-0244361, and/orSer. No. 13/260,400, filed Sep. 26, 2011, now U.S. Pat. No. 8,542,451,and/or U.S. Pat. Nos. 7,965,336 and/or 7,480,149, which are herebyincorporated herein by reference in their entireties. The imaging arraysensor may comprise any suitable sensor, and may utilize various imagingsensors or imaging array sensors or cameras or the like, such as a CMOSimaging array sensor, a CCD sensor or other sensors or the like, such asthe types described in U.S. Pat. Nos. 5,550,677; 5,670,935; 5,760,962;5,715,093; 5,877,897; 6,922,292; 6,757,109; 6,717,610; 6,590,719;6,201,642; 6,498,620; 5,796,094; 6,097,023; 6,320,176; 6,559,435;6,831,261; 6,806,452; 6,396,397; 6,822,563; 6,946,978; 7,339,149;7,038,577; 7,004,606 and/or 7,720,580, and/or U.S. patent applicationSer. No. 10/534,632, filed May 11, 2005, now U.S. Pat. No. 7,965,336,and/or PCT Application No. PCT/US2008/076022, filed Sep. 11, 2008 andpublished Mar. 19, 2009 as International Publication No. WO/2009/036176,and/or PCT Application No. PCT/US2008/078700, filed Oct. 3, 2008 andpublished Apr. 9, 2009 as International Publication No. WO/2009/046268,which are all hereby incorporated herein by reference in theirentireties.

The camera module and circuit chip or board and imaging sensor may beimplemented and operated in connection with various vehicularvision-based systems, and/or may be operable utilizing the principles ofsuch other vehicular systems, such as a vehicle headlamp control system,such as the type disclosed in U.S. Pat. Nos. 5,796,094; 6,097,023;6,320,176; 6,559,435; 6,831,261; 7,004,606; 7,339,149 and/or 7,526,103,which are all hereby incorporated herein by reference in theirentireties, a rain sensor, such as the types disclosed in commonlyassigned U.S. Pat. Nos. 6,353,392; 6,313,454; 6,320,176 and/or7,480,149, which are hereby incorporated herein by reference in theirentireties, a vehicle vision system, such as a forwardly, sidewardly orrearwardly directed vehicle vision system utilizing principles disclosedin U.S. Pat. Nos. 5,550,677; 5,670,935; 5,760,962; 5,877,897; 5,949,331;6,222,447; 6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202;6,201,642; 6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452;6,822,563; 6,891,563; 6,946,978 and/or 7,859,565, which are all herebyincorporated herein by reference in their entireties, a trailer hitchingaid or tow check system, such as the type disclosed in U.S. Pat. No.7,005,974, which is hereby incorporated herein by reference in itsentirety, a reverse or sideward imaging system, such as for a lanechange assistance system or lane departure warning system or for a blindspot or object detection system, such as imaging or detection systems ofthe types disclosed in U.S. Pat. Nos. 7,720,580; 7,038,577; 5,929,786and/or 5,786,772, and/or U.S. patent application Ser. No. 11/239,980,filed Sep. 30, 2005, now U.S. Pat. No. 7,881,496, and/or U.S.provisional applications, Ser. No. 60/628,709, filed Nov. 17, 2004; Ser.No. 60/614,644, filed Sep. 30, 2004; Ser. No. 60/618,686, filed Oct. 14,2004; Ser. No. 60/638,687, filed Dec. 23, 2004, which are herebyincorporated herein by reference in their entireties, a video device forinternal cabin surveillance and/or video telephone function, such asdisclosed in U.S. Pat. Nos. 5,760,962; 5,877,897; 6,690,268 and/or7,370,983, and/or U.S. patent application Ser. No. 10/538,724, filedJun. 13, 2005 and published Mar. 9, 2006 as U.S. Publication No.US-2006-0050018, which are hereby incorporated herein by reference intheir entireties, a traffic sign recognition system, a system fordetermining a distance to a leading or trailing vehicle or object, suchas a system utilizing the principles disclosed in U.S. Pat. Nos.6,396,397 and/or 7,123,168, which are hereby incorporated herein byreference in their entireties, and/or the like.

Optionally, the circuit board or chip may include circuitry for theimaging array sensor and or other electronic accessories or features,such as by utilizing compass-on-a-chip or EC driver-on-a-chip technologyand aspects such as described in U.S. Pat. No. 7,255,451 and/or U.S.Pat. No. 7,480,149, and/or U.S. patent application Ser. No. 11/226,628,filed Sep. 14, 2005 and published Mar. 23, 2006 as U.S. Publication No.US-2006-0061008, and/or Ser. No. 12/578,732, filed Oct. 14, 2009 andpublished Apr. 22, 2010 as U.S. Publication No. US-2010-0097469, whichare hereby incorporated herein by reference in their entireties.

Optionally, the vision system may include a display for displayingimages captured by one or more of the imaging sensors for viewing by thedriver of the vehicle while the driver is normally operating thevehicle. Optionally, for example, the vision system may include a videodisplay device disposed at or in the interior rearview mirror assemblyof the vehicle, such as by utilizing aspects of the video mirror displaysystems described in U.S. Pat. No. 6,690,268 and/or U.S. patentapplication Ser. No. 13/333,337, filed Dec. 21, 2011, now U.S. Pat. No.9,264,672, which are hereby incorporated herein by reference in theirentireties. The video mirror display may comprise any suitable devicesand systems and optionally may utilize aspects of the compass displaysystems described in U.S. Pat. Nos. 7,370,983; 7,329,013; 7,308,341;7,289,037; 7,249,860; 7,004,593; 4,546,551; 5,699,044; 4,953,305;5,576,687; 5,632,092; 5,677,851; 5,708,410; 5,737,226; 5,802,727;5,878,370; 6,087,953; 6,173,508; 6,222,460; 6,513,252 and/or 6,642,851,and/or European patent application, published Oct. 11, 2000 underPublication No. EP 0 1043566, and/or U.S. patent application Ser. No.11/226,628, filed Sep. 14, 2005 and published Mar. 23, 2006 as U.S.Publication No. US-2006-0061008, which are all hereby incorporatedherein by reference in their entireties. Optionally, the video mirrordisplay screen or device may be operable to display images captured by arearward viewing camera of the vehicle during a reversing maneuver ofthe vehicle (such as responsive to the vehicle gear actuator beingplaced in a reverse gear position or the like) to assist the driver inbacking up the vehicle, and optionally may be operable to display thecompass heading or directional heading character or icon when thevehicle is not undertaking a reversing maneuver, such as when thevehicle is being driven in a forward direction along a road (such as byutilizing aspects of the display system described in PCT Application No.PCT/US2011/056295, filed Oct. 14, 2011 and published Apr. 19, 2012 asInternational Publication No. WO 2012/051500, which is herebyincorporated herein by reference in its entirety).

Optionally, the vision system (utilizing the forward facing camera and arearward facing camera and other cameras disposed at the vehicle withexterior fields of view) may be part of or may provide a display of atop-down view or birds-eye view system of the vehicle or a surround viewat the vehicle, such as by utilizing aspects of the vision systemsdescribed in International Publication Nos. WO 2010/099416; WO2011/028686; WO 2012/075250; WO 2013/019795; WO 2012/075250; WO2012/145822; WO 2013/081985; WO 2013/086249 and/or WO 2013/109869,and/or U.S. patent application Ser. No. 13/333,337, filed Dec. 21, 2011,now U.S. Pat. No. 9,264,672, which are hereby incorporated herein byreference in their entireties.

Optionally, a video mirror display may be disposed rearward of andbehind the reflective element assembly and may comprise a display suchas the types disclosed in U.S. Pat. Nos. 5,530,240; 6,329,925;7,855,755; 7,626,749; 7,581,859; 7,446,650; 7,370,983; 7,338,177;7,274,501; 7,255,451; 7,195,381; 7,184,190; 5,668,663; 5,724,187 and/or6,690,268, and/or in U.S. patent application Ser. No. 12/091,525, filedApr. 25, 2008, now U.S. Pat. No. 7,855,755; Ser. No. 11/226,628, filedSep. 14, 2005 and published Mar. 23, 2006 as U.S. Publication No.US-2006-0061008, and/or Ser. No. 10/538,724, filed Jun. 13, 2005 andpublished Mar. 9, 2006 as U.S. Publication No. US-2006-0050018, whichare all hereby incorporated herein by reference in their entireties. Thedisplay is viewable through the reflective element when the display isactivated to display information. The display element may be any type ofdisplay element, such as a vacuum fluorescent (VF) display element, alight emitting diode (LED) display element, such as an organic lightemitting diode (OLED) or an inorganic light emitting diode, anelectroluminescent (EL) display element, a liquid crystal display (LCD)element, a video screen display element or backlit thin film transistor(TFT) display element or the like, and may be operable to displayvarious information (as discrete characters, icons or the like, or in amulti-pixel manner) to the driver of the vehicle, such as passenger sideinflatable restraint (PSIR) information, tire pressure status, and/orthe like. The mirror assembly and/or display may utilize aspectsdescribed in U.S. Pat. Nos. 7,184,190; 7,255,451; 7,446,924 and/or7,338,177, which are all hereby incorporated herein by reference intheir entireties. The thicknesses and materials of the coatings on thesubstrates of the reflective element may be selected to provide adesired color or tint to the mirror reflective element, such as a bluecolored reflector, such as is known in the art and such as described inU.S. Pat. Nos. 5,910,854; 6,420,036 and/or 7,274,501, which are herebyincorporated herein by reference in their entireties.

Optionally, the display or displays and any associated user inputs maybe associated with various accessories or systems, such as, for example,a tire pressure monitoring system or a passenger air bag status or agarage door opening system or a telematics system or any other accessoryor system of the mirror assembly or of the vehicle or of an accessorymodule or console of the vehicle, such as an accessory module or consoleof the types described in U.S. Pat. Nos. 7,289,037; 6,877,888;6,824,281; 6,690,268; 6,672,744; 6,386,742 and 6,124,886, and/or U.S.patent application Ser. No. 10/538,724, filed Jun. 13, 2005 andpublished Mar. 9, 2006 as U.S. Publication No. US-2006-0050018, whichare hereby incorporated herein by reference in their entireties.

While the above description constitutes a plurality of embodiments ofthe present invention, it will be appreciated that the present inventionis susceptible to further modification and change without departing fromthe fair meaning of the accompanying claims.

The invention claimed is:
 1. A vehicular vision system, said vehicularvision system comprising: a plurality of cameras disposed at a vehicleequipped with said vision system; wherein said plurality of camerascomprises at least a first camera, a second camera, a third camera and afourth camera; each of said first camera, said second camera, said thirdcamera and said fourth camera having a respective field of view exteriorof the equipped vehicle; each of said first camera, said second camera,said third camera and said fourth camera being operable to captureframes of image data; an electronic control unit (ECU); wherein imagedata captured by said first camera is provided to the ECU via a firstETHERNET link from said first camera to the ECU; wherein image datacaptured by said second camera is provided to the ECU via a secondETHERNET link from said second camera to the ECU; wherein image datacaptured by said third camera is provided to the ECU via a thirdETHERNET link from said third camera to the ECU; wherein image datacaptured by said fourth camera is provided to the ECU via a fourthETHERNET link from said fourth camera to the ECU; wherein at least onecontrol signal is provided from the ECU to said first camera via saidfirst ETHERNET link; wherein at least one control signal is providedfrom the ECU to said second camera via said second ETHERNET link;wherein at least one control signal is provided from the ECU to saidthird camera via said third ETHERNET link; wherein at least one controlsignal is provided from the ECU to said fourth camera via said fourthETHERNET link; wherein first camera calibration data is provided fromsaid first camera to the ECU via said first ETHERNET link; whereinsecond camera calibration data is provided from said second camera tothe ECU via said second ETHERNET link; wherein third camera calibrationdata is provided from said third camera to the ECU via said thirdETHERNET link; wherein fourth camera calibration data is provided fromsaid fourth camera to the ECU via said fourth ETHERNET link; whereinsaid first camera is disposed at a front portion of the equippedvehicle, and wherein said second camera is disposed at a driver-sideside portion of the equipped vehicle, and wherein said third camera isdisposed at a passenger-side side portion of the equipped vehicle, andwherein said fourth camera is disposed at a rear portion of the equippedvehicle; wherein image data captured by at least one of said firstcamera, said second camera, said third camera and said fourth camera isprocessed at the ECU to detect an object present exterior of theequipped vehicle; wherein the object present exterior of the equippedvehicle is exterior a side of the equipped vehicle; wherein the objectpresent exterior the side of the equipped vehicle comprises a vehiclethat is approaching the equipped vehicle; and wherein the vehicle thatis approaching the equipped vehicle is traveling in a traffic laneadjacent to a traffic lane in which the equipped vehicle is traveling.2. The vehicular vision system of claim 1, wherein image data capturedrespectively by at least one of said first, second, third and fourthcameras is provided to the ECU via a hub.
 3. The vehicular vision systemof claim 1, wherein said first camera, said second camera, said thirdcamera and said fourth camera are part of a surround view system of theequipped vehicle.
 4. The vehicular vision system of claim 3, whereinimage data captured by at least one of said first camera, said secondcamera, said third camera and said fourth camera is processed at theECU, and wherein, responsive at least in part to said processing, theECU outputs images for display at a display device of the equippedvehicle for viewing by a driver of the equipped vehicle.
 5. Thevehicular vision system of claim 4, wherein the displayed imagescomprise a birds-eye view.
 6. The vehicular vision system of claim 3,wherein said first camera comprises a first megapixel imaging arrayhaving at least one million photosensing elements arranged in columnsand rows of photosensing elements, and wherein said second cameracomprises a second megapixel imaging array having at least one millionphotosensing elements arranged in columns and rows of photosensingelements, and wherein said third camera comprises a third megapixelimaging array having at least one million photosensing elements arrangedin columns and rows of photosensing elements, and wherein said fourthcamera comprises a fourth megapixel imaging array having at least onemillion photosensing elements arranged in columns and rows ofphotosensing elements.
 7. The vehicular vision system of claim 1,wherein the object present exterior of the equipped vehicle is to therear of the equipped vehicle and is detected during a reversing maneuverof the equipped vehicle.
 8. The vehicular vision system of claim 1,wherein said first camera comprises a first megapixel CMOS imaging arrayhaving at least one million photosensing elements arranged in columnsand rows of photosensing elements, and wherein said second cameracomprises a second megapixel CMOS imaging array having at least onemillion photosensing elements arranged in columns and rows ofphotosensing elements, and wherein said third camera comprises a thirdmegapixel CMOS imaging array having at least one million photosensingelements arranged in columns and rows of photosensing elements, andwherein said fourth camera comprises a fourth megapixel CMOS imagingarray having at least one million photosensing elements arranged incolumns and rows of photosensing elements.
 9. The vehicular visionsystem of claim 1, wherein, upon powering said first, second, third andfourth cameras, the first, second, third and fourth ETHERNET links areinitialized to establish communication with the respective first,second, third and fourth cameras.
 10. The vehicular vision system ofclaim 9, wherein the established communication at least comprises thefirst, second, third, and fourth camera calibration data for therespective cameras.
 11. The vehicular vision system of claim 1, whereinsaid first camera receives from the ECU via said first ETHERNET link afirst camera control signal that regulates timing of said first camerato be synchronous with reference timing of the ECU, and wherein saidsecond camera receives from the ECU via said second ETHERNET link asecond camera control signal that regulates timing of said second camerato be synchronous with reference timing of the ECU, and wherein saidthird camera receives from the ECU via said third ETHERNET link a thirdcamera control signal that regulates timing of said third camera to besynchronous with reference timing of the ECU, and wherein said fourthcamera receives from the ECU via said fourth ETHERNET link a fourthcamera control signal that regulates timing of said fourth camera to besynchronous with reference timing of the ECU.
 12. The vehicular visionsystem of claim 11, wherein regulation of timing of said first cameracomprises starting said first camera synchronous to the ECU referencetiming and holding said first camera synchronous to the ECU referencetiming, and wherein regulation of timing of said second camera comprisesstarting said second camera synchronous to the ECU reference timing andholding said second camera synchronous to the ECU reference timing, andwherein regulation of timing of said third camera comprises startingsaid third camera synchronous to the ECU reference timing and holdingsaid third camera synchronous to the ECU reference timing, and whereinregulation of timing of said fourth camera comprises starting saidfourth camera synchronous to the ECU reference timing and holding saidfourth camera synchronous to the ECU reference timing.
 13. A vehicularvision system, said vehicular vision system comprising: a plurality ofcameras disposed at a vehicle equipped with said vision system; whereinsaid plurality of cameras comprises at least a first camera, a secondcamera, a third camera and a fourth camera; each of said first camera,said second camera, said third camera and said fourth camera having arespective field of view exterior of the equipped vehicle; each of saidfirst camera, said second camera, said third camera and said fourthcamera being operable to capture frames of image data; wherein saidfirst camera, said second camera, said third camera and said fourthcamera are part of a surround view system of the equipped vehicle; anelectronic control unit (ECU); wherein image data captured by said firstcamera is provided to the ECU via a first ETHERNET link from said firstcamera to the ECU; wherein image data captured by said second camera isprovided to the ECU via a second ETHERNET link from said second camerato the ECU; wherein image data captured by said third camera is providedto the ECU via a third ETHERNET link from said third camera to the ECU;wherein image data captured by said fourth camera is provided to the ECUvia a fourth ETHERNET link from said fourth camera to the ECU; whereinat least one control signal is provided from the ECU to said firstcamera via said first ETHERNET link; wherein at least one control signalis provided from the ECU to said second camera via said second ETHERNETlink; wherein at least one control signal is provided from the ECU tosaid third camera via said third ETHERNET link; wherein at least onecontrol signal is provided from the ECU to said fourth camera via saidfourth ETHERNET link; wherein first camera calibration data is providedfrom said first camera to the ECU via said first ETHERNET link; whereinsecond camera calibration data is provided from said second camera tothe ECU via said second ETHERNET link; wherein third camera calibrationdata is provided from said third camera to the ECU via said thirdETHERNET link; wherein fourth camera calibration data is provided fromsaid fourth camera to the ECU via said fourth ETHERNET link; wherein,upon powering said first camera, said first ETHERNET link is initializedto establish communication with said first camera; wherein, uponpowering said second camera, said second ETHERNET link is initialized toestablish communication with said second camera; wherein, upon poweringsaid third camera, said third ETHERNET link is initialized to establishcommunication with said third camera; wherein, upon powering said fourthcamera, said fourth ETHERNET link is initialized to establishcommunication with said fourth camera; wherein said first camera isdisposed at a front portion of the equipped vehicle, and wherein saidsecond camera is disposed at a driver-side side portion of the equippedvehicle, and wherein said third camera is disposed at a passenger-sideside portion of the equipped vehicle, and wherein said fourth camera isdisposed at a rear portion of the equipped vehicle; wherein image datacaptured by at least one of said first camera, said second camera, saidthird camera and said fourth camera is processed at the ECU to detect anobject present exterior of the equipped vehicle; wherein the objectpresent exterior of the equipped vehicle is exterior a side of theequipped vehicle; wherein the object present exterior the side of theequipped vehicle comprises a vehicle that is approaching the equippedvehicle; and wherein the vehicle that is approaching the equippedvehicle traveling in a traffic lane adjacent to a traffic lane in whichthe equipped vehicle is traveling.
 14. The vehicular vision system ofclaim 13, wherein image data captured respectively by at least one ofsaid first, second, third and fourth cameras is provided to the ECU viaa hub.
 15. The vehicular vision system of claim 13, wherein image datacaptured by at least one of said first camera, said second camera, saidthird camera and said fourth camera is processed at the ECU, andwherein, responsive at least in part to said processing, the ECU outputsimages for display at a display device of the equipped vehicle forviewing by a driver of the equipped vehicle.
 16. The vehicular visionsystem of claim 15, wherein the displayed images comprise a birds-eyeview.
 17. A vehicular vision system, said vehicular vision systemcomprising: a plurality of cameras disposed at a vehicle equipped withsaid vision system; wherein said plurality of cameras comprises at leasta first camera, a second camera, a third camera and a fourth camera;wherein said first camera comprises a first megapixel imaging arrayhaving at least one million photosensing elements arranged in columnsand rows of photosensing elements; wherein said second camera comprisesa second megapixel imaging array having at least one millionphotosensing elements arranged in columns and rows of photosensingelements; wherein said third camera comprises a third megapixel imagingarray having at least one million photosensing elements arranged incolumns and rows of photosensing elements; wherein said fourth cameracomprises a fourth megapixel imaging array having at least one millionphotosensing elements arranged in columns and rows of photosensingelements; each of said first camera, said second camera, said thirdcamera and said fourth camera having a respective field of view exteriorof the equipped vehicle; each of said first camera, said second camera,said third camera and said fourth camera being operable to captureframes of image data; wherein said first camera, said second camera,said third camera and said fourth camera are part of a surround viewsystem of the equipped vehicle; an electronic control unit (ECU);wherein image data captured by said first camera is provided to the ECUvia a first ETHERNET link from said first camera to the ECU; whereinimage data captured by said second camera is provided to the ECU via asecond ETHERNET link from said second camera to the ECU; wherein imagedata captured by said third camera is provided to the ECU via a thirdETHERNET link from said third camera to the ECU; wherein image datacaptured by said fourth camera is provided to the ECU via a fourthETHERNET link from said fourth camera to the ECU; wherein at least onecontrol signal is provided from the ECU to said first camera via saidfirst ETHERNET link; wherein at least one control signal is providedfrom the ECU to said second camera via said second ETHERNET link;wherein at least one control signal is provided from the ECU to saidthird camera via said third ETHERNET link; wherein at least one controlsignal is provided from the ECU to said fourth camera via said fourthETHERNET link; wherein first camera calibration data is provided fromsaid first camera to the ECU via said first ETHERNET link; whereinsecond camera calibration data is provided from said second camera tothe ECU via said second ETHERNET link; wherein third camera calibrationdata is provided from said third camera to the ECU via said thirdETHERNET link; wherein fourth camera calibration data is provided fromsaid fourth camera to the ECU via said fourth ETHERNET link; whereinsaid first camera is disposed at a front portion of the equippedvehicle, and wherein said second camera is disposed at a driver-sideside portion of the equipped vehicle, and wherein said third camera isdisposed at a passenger-side side portion of the equipped vehicle, andwherein said fourth camera is disposed at a rear portion of the equippedvehicle; wherein image data captured by at least one of said firstcamera, said second camera, said third camera and said fourth camera isprocessed at the ECU to detect an object present exterior of theequipped vehicle; wherein the object present exterior of the equippedvehicle is exterior a side of the equipped vehicle; wherein the objectpresent exterior the side of the equipped vehicle comprises a vehiclethat is approaching the equipped vehicle; wherein the vehicle that isapproaching the equipped vehicle traveling in a traffic lane adjacent toa traffic lane in which the equipped vehicle is traveling; and whereinimage data captured by at least one of said first camera, said secondcamera, said third camera and said fourth camera is processed at theECU, and wherein, responsive at least in part to said processing, theECU outputs images for display at a display device of the equippedvehicle for viewing by a driver of the equipped vehicle.
 18. Thevehicular vision system of claim 17, wherein the displayed imagescomprise a birds-eye view.
 19. The vehicular vision system of claim 17,wherein said first camera receives from the ECU via said first ETHERNETlink a first camera control signal that regulates timing of said firstcamera to be synchronous with reference timing of the ECU, and whereinsaid second camera receives from the ECU via said second ETHERNET link asecond camera control signal that regulates timing of said second camerato be synchronous with reference timing of the ECU, and wherein saidthird camera receives from the ECU via said third ETHERNET link a thirdcamera control signal that regulates timing of said third camera to besynchronous with reference timing of the ECU, and wherein said fourthcamera receives from the ECU via said fourth ETHERNET link a fourthcamera control signal that regulates timing of said fourth camera to besynchronous with reference timing of the ECU.
 20. The vehicular visionsystem of claim 19, wherein regulation of timing of said first cameracomprises starting said first camera synchronous to the ECU referencetiming and holding said first camera synchronous to the ECU referencetiming, and wherein regulation of timing of said second camera comprisesstarting said second camera synchronous to the ECU reference timing andholding said second camera synchronous to the ECU reference timing, andwherein regulation of timing of said third camera comprises startingsaid third camera synchronous to the ECU reference timing and holdingsaid third camera synchronous to the ECU reference timing, and whereinregulation of timing of said fourth camera comprises starting saidfourth camera synchronous to the ECU reference timing and holding saidfourth camera synchronous to the ECU reference timing.